A Kitty Pryde movie is in development at Fox from Deadpool's Tim Miller.
The movie is reported by Collider to be "very much" in development as business at Fox continues to operate as usual but, with the Disney acquisition on the horizon, it is not guaranteed to become a real film simply by reaching such a stage.
Fox currently has New Mutants, The Untitled Deadpool Sequel, and X-Men: The Phoenix Force set for release in 2018. The trio of production-completed films are guaranteed to arrive, although the X-Men have been promised to merge with the Marvel Cinematic Universe following the Disney/Fox deal. Fox becoming an entity of Disney of one of many things which could prevent the film from ever heading toward production but the development is a clear sign that Fox has no plans to slow down as they look toward the uncertain future.
The X-Men character Kitty Pryde, also known as Shadowcat, has appeared in a number of films. Most recently, Ellen Page played the character in X-Men: Days of Future Past. With Miller, who directed the original Deadpool movie which released in 2016, working on the film, the immediate speculation will raise the question of whether or not Ryan Reynolds' character will crossover into the film. However, there is no word on any such ties just yet.
The Untitled Deadpool sequel is set for release on June 1, 2018.